1. Field of Invention
This invention relates to an adjustable crutch having a spring-loaded retractable metal point or spike element.
2. Description of the Prior Art
Adjustable crutches having a retractable point or spike are known in the art such as in U.S. Pat. Nos. 39,684; 332,684; 404,303; 1,652,110; 2,358,853; 3,646,949; 3,757,807 and 3,901,258. All of these crutches have serious shortcomings, however, as demonstrated by the fact that none to our knowledge have gained commercial success. For example, each of these prior art crutches suffer from one or more of the following shortcomings:
(a) The crutch cannot be quickly and conveniently modified from a structure adapted for outdoor use to one adapted for indoor use.
(b) The point or spike of the crutch is often rigid and consequently has a tendency to bend or break when called on to support the user's entire weight. Additionally, rigid points (as opposed to spring-loaded) tend to slip on hard ice if they do not make immediate penetration on contact with the ice.
(c) The crutch is unable to accommodate irregular surfaces when the spike is in projected position.
(d) No adjustment is possible to change point pressure.
(e) The mechanism of the crutch is not sufficiently protected against the elements and may jam or become inoperable in time.
(f) The crutch cannot be adjusted to accommodate changing surface conditions.
(g) The crutch is not strong and safe enough for use by all patients.
These and other shortcomings are all avoided by the present invention.